"Though [Scrooge] looked the phantom through and through, and saw it standing before him; though he felt the chilling influence of its death-cold eyes; and marked the very texture of the folded kerchief bound about its head and chin, which wrapper he had not observed before; he was still incredulous, and fought against his senses. But how much greater was his horror, when the phantom taking off the bandage round its head, as if it were too warm to wear in-doors, its lower jaw dropped down upon its breast!"

It does seem indicated by this passage that Marley died from some sort of head ailment. We can assume one of two things: either the bandage is part of the treatment (like a poultice), or the bandage is a result of the treatment (like a way to stop bleeding after surgery).

Poultices, held to the head with bandages, were commonly used to ease pain or swelling, such as could be caused by a tooth or ear infection. When Dickens wrote "A Christmas Carol," the treatment for toothaches was often pulling teeth, and antibiotics hadn't been developed yet. As the roots of the teeth are so close to the brain, it is possible that a tooth infection could have spread to the brain. According to Dr. Martin S. Spiller, D.M.D:

"In the days before antibiotics and modern surgery, dental abscess was a common cause of death. Upon occasion, especially in the case of an untreated abscess of an upper front tooth, the patient can get a brain abscess which can kill him. This brain infection is called cavernous sinus thrombosis. Another killer is Ludwig's angina. This infection is caused by an abscess of a lower back tooth. The major symptom is severe swelling under the tongue, chin and neck. The swelling may become so severe that the patient can no longer breath. During and after the renaissance, but before the advent of modern dentistry, this infection was one of the most frequent causes of death, particularly among the wealthy upper classes who had access to large amounts of sugar." (http://www.doctorspiller.com/Root_Canals.htm)

Ear infection, especially infection of the bones behind ear, called mastoiditis, could be a culprit. Again, this infection could be fatal because of the closeness to the brain. According to Dr. Jennifer L Parker, "Prior to the discovery of antibiotics, acute mastoiditis was the most common complication of acute otitis media [ear infection] and often resulted in death." (http://www.bcm.edu/oto/grand/2394.html)

Other illnesses, such as aneurysms and tumors, would sometimes have been treated with surgery, which has been around since the late Stone Age (http://www.brain-surgery.com/history.html). This was done with little thought to what we now consider basic cleanliness, so infection would have been highly likely.

There is the possibility he may have had head trauma (such as a concussion or fracture) from an accident, and later died from complications.

But my favorite theory is that of oral cancer. The habit of smoking cigars and cigarettes was popular in Victorian England. (http://www.wramc.army.mil/education/tobaccohistory.htm) If we can assume the tightwad Marley may have indulged in the practice of smoking, especially cigars, it's possible he may have developed oral cancer, which could explain his jaw dropping after he removes the bandage.

I hope this helps your research. If you have any further questions, please feel free to let us know!

[This comment was originally posted by mwladich and reposted here by tiantian]

I recalled that bandages were used to bind the jaw to keep it from suddenly dropping in front of the mourners and upsetting them further. If this was the case, then the bandage cannot be used solely for clues as to what killed Marley. I went to confirm my memory and I was fortunate to find a book about embalming that was written in 1838 by a Frenchman. A Christmas Carol was written in 1843. It turns out that bandages were used extensively in the preparation for burial. The French author's name was Gannal.

Monsieur Jean Nicholas Gannal's book is called History of Embalming: and Of Preparations In Anatomy, Pathology and Natural History: Including An Account of a New Process for Embalming. An English edition, translated from French by Richard Harlan and published by Judah Dobson came out in 1840. It must have been a hit from the way his bio was written up in another book.

Anyway here are some interesting passages. It never says specifically that the jaw is to be bound to keep it from dropping suddenly, but special care was afforded to wrap the head in order to preserve it.The brain was removed by sawing off the top of the cranium. Then the top of the cranium was reattached by other processes and hidden by resins and wax, etc. You want to hide that.

Pg. 102 on supplies that the professional embalmer should keep with him.

"The embalmer ought to furnish himself with silk ribands (this isn't a typo, but his old style English spelling) of black, violet, or white colour according to the subject which he has to embalm in order to tie the sheet by the two extremities, as well as a quarter of taffeta of one of the said colours to envelope the box of the heart; further, 5 fathoms of cord to tie the corpse enveloped in the cere-cloth."

I saw violet cloths wrapping the heads of the Russian children who were terrorist victims in a photo.

pg. 127 on the preservation of the corpse of a 10 year old girl

....the eyelids and lips were kept closed with English Taffeta." Without wiring the jaw shut which is what we do today, (Embalming: History, Theory, and Practice, 1990, Appelton & Lange, E. Norwalk, CT pgs 201-206 illustrates how wiring or sewing the jaw shut is done today. Literally.) the one way to keep the lips shut is to tie the head like Marley.

But pages 130 and 135 seem to illustrate best that Marley's body might have been treated as such...

Pg 130
on the 8th step of embalming King Louis the 18th

The limbs, the pelvis, the abdomen the chest, the neck and the head were successively surrounded by bandages, methodically applied.

pg 135
...it is only that methodical bandages are made to cover all parts, from the fingers and toes to the head.

Overall, Msr. Gannal was an incredibly intelligent man by the way he wrote. He was very professional too and didn't make the text sound gloomy or gross at all. In fact, it was an interesting window of everyday life, or rather death, of what it was like over 160 years ago. For instance he advocated the "safer method" of injecting parts of one chemical and parts arsenic into the corpse to preserve it. He also played with mercury. Formaldehyde had not been discovered yet and neither were the dangers of playing with arsenic and mercury. He also advised to make a slash at the bottom of the foot first before doing anything at all to the corpse to make sure the subject really was dead since being buried alive was a real possibility in those days. Cheery subject isn't it?

But re-read that passage in A Christmas Carol where Marley is approaching Scrooge. When Marley removes his ribbon so that his jaw drops to his chest, you can now see the freak out factor in this. It would serve to remind Scrooge that yes, his friend and partner really is "dead as a doornail".